One is a television series depicting an ageing rock star, desperately hanging on to his stardom while he struggles with wayward children and misbehaving household items.

The other is The Osbournes. And now lawyers for Ozzy Osbourne, the former lead singer of Black Sabbath whose domestic life has been turned into a runaway television success, are on the warpath. They are writing to Harry Enfield, who is creating his own BBC sitcom about a veteran rock star, warning him to "immediately cease and desist from the inclusion of any characters in the show based on Mr Osbourne or any other member of his family".

All of which has left Enfield nonplussed – for the rock star on which his series is based is a fictional one who has appeared since 1987 in the Private Eye cartoon "Celeb", created by Charles Peattie and Russell Taylor. "I haven't watched a single Osbourne programme," Enfield said. He had been writing scripts for his new programme, also called Celeb, for "two or three years", he said.

The first of six episodes on BBC 1 will be screened next month, depicting Gary Bloke, a fading rocker rich enough not to care if no one buys his records but desperate still to be considered a star. He lives on a country estate in "Rockmansionshire", drives a chrome-plated, turbo-charged lawnmower and struggles to hang on to his younger wife.There was no response from the Osbournes' lawyers.